Monkey diving is the use of sidemount configuration/procedures, whilst only carrying a single cylinder. It is presented as an option on some recreational level sidemount courses (dependant on agency) and may also be a considered strategy for certain overhead-environment (cave/wreck) penetrations. The use of a single cylinder may require a strategy of counter-weighting to prevent diver instability in the water, depending on the buoyancy of the chosen cylinder.
Disclaimer: Monkey Diving is extremely dangerous, it can kill you. Do not try this at home.
First and foremost let me state that you must receive formal training from one of the many dive organisations before attempting a dive. Without formal training you risk injuring yourself. Please get training before attempting anything you have read or seen in this post. I will not be held responsible for you attempting to use the methods contained in this post. The following post is for illustration purposes only.
I have monkey dived before. When I was helping teach an Open Water course at Bainbridge Quarry I dived in my sidemount harness with a single tank. I found it easy enough to do although you do feel a little lopsided but it is possible to adjust yourself so that it doesn’t affect you that much.
So how how do you get ready for monkey diving?
First and foremost it is usually conducted with out the aid of a BCD (Buoyancy Control Device) or a BAT wing (Buoyancy and Trim), however you should have a harness to attach the cylinder to; usually in a sidemount configuration. You need to be properly weighted so that you are negatively buoyant when you exhale and positively buoyant when you inhale. You do this first while wearing your choice of exposure protection, and then again with the cylinder attached. Then you are pretty much ready to go diving.
How did I do it?
Although I chose to dive in an 8/7mm semi-dry in the Bainbridge Quarry, here in the Bahamas I opted for just diving in my shorts. I even chose not to dive with a harness, instead I just tucked the cylinder under my arm. This is inherently dangerous. My left arm is now rendered useless. It is now holding the tank and keeping it trimmed against the side of my body. The cylinder is not attached to anything and could slip away. I have no octopus to donate. My primary second stage is strapped to my face making it almost impossible to donate safely. Please do not dive like this.
So why would I dive like this if it is so dangerous?
The maximum depth I was at was 8m. Well within the PADI’s guidelines for performing a CESA (Controlled Emergency Swimming Ascent), and I have performed lots of CESAs in my time when instructing Open Water students. I had a buddy with me. Although he wasn’t diving, he is scuba trained and was snorkelling at the surface. There were a dozen certified scuba divers on the beach, many of which were rescue divers or higher. There were also three boats that were visiting the site, two contained snorkellers and the other contained divers. So there was a lot of backup available. There were no overhead environments that I could become trapped under, and I kept myself away from the the corals and other vegetation so that I would not get stung by anything.
Diving is all about mitigating risk. It is impossible to remove it completely but it is possible to make the risks so small that it becomes less dangerous. The more experienced you become the more understanding you have of what you are capable of and what you should stay away from. Would I dive like this all the time? Probably not. It task-loads you and if you aren’t comfortable with being task-loaded then you should stay away from that kind of diving. There is no redundancy. I like diving with two tanks, and not just because it looks cool, but because I have a secondary source of air if I was to have any failure.
The main reason as to why I chose to dive like this is because it puts you in complete touch with your buoyancy. It is all about lung control and even though I have really good buoyancy, bordering on exceptional, it can still do with some work and fine tuning. I was able to hover quite comfortably. I did find it difficult when making ascents and that is something that I would have to practice. I am sure if the conditions are right I will try it again soon, maybe with a belt and some d-rings so that the tank can be attached to me.